This invention relates to hydraulic compositions, products formed therefrom and segregation reduction agents for hydraulic substances, which compositions contain .beta.-1,3-glucan, and which exhibit high fluidity, high filling capacity, and which are very high in resistance to segregation and useful for such as mortar or concrete.
Technology which imparts high fluidity to concrete and which gives it high filling capacity and makes it possible to pour the concrete without consolidation has been disclosed as the so-called "high performance concrete" developed by Professor Okamura of the Department of Engineering of Tokyo University (see Doboku Seko, October 1989). Also, viscosity improving agents have been added to concrete to prevent segregation of the ingredients in the mortar or concrete.
The following problems are, however, associated with the prior art.
(a) In the case of high performance concrete, it is necessary to carefully select the materials in order to produce a concrete which has a very high powder content and moreover, small amounts of viscosity enhancers must be used in order to prevent separation of the concrete while it is in the fluid state. Because of this, very careful quality control must be exercised over the materials being used, and strict production control is also required. It is quite difficult to perform on-site formulation and utilization of this type of concrete.
(b) Concrete to which antiwashout admixtures have been added to prevent segregation has poor fluidity, so when it is poured into highly reinforced forms, it is very difficult to achieve proper filling without consolidation. Also, because it has a large unit water content, the water density declines which lowers its resistance to carbonation, causes a high degree of shrinkage during drying, and which, due to the large air bubbles within, causes lowered resistance to freezing and thawing and thus, lowered durability.
The object of this invention is to improve upon the above described problems and provide hydraulic compositions, products formed thereafter and separation reduction agents, useful for such as mortar or concrete, which offer high fluidity, high filling capacity, and high resistance to segregation which make it possible to pour the concrete without consolidation and still achieve excellent durability.